late 14c., "stated explicitly, not implied, clearly made known" from Old French espres, expres (13c.), from Latin expressus "clearly presented, distinct, articulated precisely," past participle of exprimere (see express (v.1)). Also late 14c. as an adverb, "specially, on purpose;" it also doubled as an adverb in Old French. An express train (1841) originally was one that ran to a certain station.